NCERT Solutions for Class 12 Maths Chapter 8 Application of Integrals Ex 8.1 are part of NCERT Solutions for Class 12 Maths. Here we have given NCERT Solutions for Class 12 Maths Chapter 8 Application of Integrals Ex 8.1.

Board |
CBSE |

Textbook |
NCERT |

Class |
Class 12 |

Subject |
Maths |

Chapter |
Chapter 8 |

Chapter Name |
Application of Integrals |

Exercise |
Ex 8.1 |

Number of Questions Solved |
13 |

Category |
NCERT Solutions |

## NCERT Solutions for Class 12 Maths Chapter 8 Application of Integrals Ex 8.1

**Ex 8.1 Class 12 Maths Question 1.**

Find the area of the region bounded by the curve y² = x and the lines x = 1, x = 4, and the x-axis.

**Solution:**

The curve y² = x is a parabola with vertex at origin.Axis of x is the line of symmetry, which is the axis of parabola. The area of the region bounded by the curve, x = 1, x=4 and the x-axis. Area LMQP

**Ex 8.1 Class 12 Maths Question 2.**

Find the area of the region bounded by y² = 9x, x = 2, x = 4 and x-axis in the first quadrant

**Solution:**

The given curve is y² = 9x, which is a parabola with vertex at (0, 0) and axis along x-axis. It is symmetrical about x-axis, as it contains only even powers of y. x = 2 and x = 4 are straight lines parallel toy-axis at a positive distance of 2 and 4 units from it respectively.

∴ Required area = Area ABCD

**Ex 8.1 Class 12 Maths Question 3.**

Find the area of the region bounded by x² = 4y, y = 2, y = 4 and the y-axis in the first quadrant.

**Solution:**

The given curve x² = 4y is a parabola with vertex at (0,0). Also since it contains only even powers of x,it is symmetrical about y-axis.y = 2 and y = 4 are straight lines parallel to x-axis at a positive distance of 2 and 4 from it respectively.

**Ex 8.1 Class 12 Maths Question 4.**

Find the area of the region bounded by the ellipse \(\frac { { x }^{ 2 } }{ 16 } +\frac { { y }^{ 2 } }{ 9 } =1\)

**Solution:**

The equation of the ellipse is \(\frac { { x }^{ 2 } }{ 16 } +\frac { { y }^{ 2 } }{ 9 } =1\)

The given ellipse is symmetrical about both axis as it contains only even powers of y and x.

**Ex 8.1 Class 12 Maths Question 5.**

Find the area of the region bounded by the ellipse \(\frac { { x }^{ 2 } }{ 4 } +\frac { { y }^{ 2 } }{ 9 } =1\)

**Solution:**

\(\frac { { x }^{ 2 } }{ 4 } +\frac { { y }^{ 2 } }{ 9 } =1\) It is an ellipse with centre (0,0) and length of major axis = 2a = 2×3 = 6 and length of minor axis = 2b = 2 × 2 = 4.

**Ex 8.1 Class 12 Maths Question 6.**

Find the area of the region in the first quadrant enclosed by x-axis, line x = √3y and the circle x² + y² = 4. .

**Solution:**

Consider the two equations x² + y² = 4 … (i)

and x = √3y i.e. \(y=\frac { 1 }{ \sqrt { 3 } } x\) …(ii)

(1) x² + y² = 4 is a circle with centre O (0,0) and radius = 2.

**Ex 8.1 Class 12 Maths Question 7.**

Find the area of the smaller part of the circle x² + y² = a² cut off by the line \(x=\frac { a }{ \sqrt { 2 } } \)

**Solution:**

The equation of the given curve are

x² + y² = a² …(i) and \(x=\frac { a }{ \sqrt { 2 } } \) …(ii)

Clearly, (i) represent a circle and (ii) is the equation of a straight line parallel to y-axis at a

**Ex 8.1 Class 12 Maths Question 8.**

The area between x = y² and x = 4 is divided into two equal parts by the line x = a, find the value of a.

**Solution:**

Graph of the curve x = y² is a parabola as given in the figure. Its vertex is O and axis is x-axis. QR is the ordinate along x = 4

**Ex 8.1 Class 12 Maths Question 9.**

Find the area of the region bounded by the parabola y = x² and y = |x|.

**Solution:**

Clearly x² = y represents a parabola with vertex at (0, 0) positive direction of y-axis as its axis it opens upwards.

y = |x| i.e., y = x and y = -x represent two lines passing through the origin and making an angle of 45° and 135° with the positive direction of the x-axis.

The required region is the shaded region as shown in the figure. Since both the curve are symmetrical about y-axis. So,

Required area = 2 (shaded area in the first quadrant)

**Ex 8.1 Class 12 Maths Question 10.**

Find the area bounded by the curve x² = 4y and the line x = 4y – 2

**Solution:**

Given curve is x² = 4y …(i)

which is an upward parabola with vertex at (0,0) and it is symmetrical about y-axis

Equation of the line is x = 4y – 2 …(ii)

Solving (i) and (ii) simultaneously, we get; (4y – 2)² = 4y

⇒ 16y² – 16y + 4 = 4y

⇒ 4y² – 5y + 1 = 0

**Ex 8.1 Class 12 Maths Question 11.**

Find the area of the region bounded by the curve y² = 4x and the line x = 3.

**Solution:**

The curve y² = 4x is a parabola as shown in the figure. Axis of the parabola is x-axis. The area of the region bounded by the curve y² = 4x and the line x = 3 is

A = Area of region OPQ = 2 (Area of the region OLQ)

Choose the correct answer in the following Exercises 12 and 13:

**Ex 8.1 Class 12 Maths Question 12.**

Area lying in the first quadrant and bounded by the circle x² + y² = 4 and the lines x = 0 and x = 2 is

(a) π

(b) \(\frac { \pi }{ 2 } \)

(c) \(\frac { \pi }{ 3 } \)

(d) \(\frac { \pi }{ 4 } \)

**Solution:**

(a) x² + y² = 4. It is a circle at the centre (0,0) and r=2

**Ex 8.1 Class 12 Maths Question 13.**

Area of the region bounded by the curve y² = 4x, y-axis and the line y = 3 is

(a) 2

(b) \(\frac { 9 }{ 4 }\)

(c) \(\frac { 9 }{ 3 }\)

(d) \(\frac { 9 }{ 2 }\)

**Solution:**

(b) y² = 4x is a parabola

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